1. Field of the Invention
The present invention relates in general to an air bag device that is mounted in a motor vehicle and expands an air bag to protect a vehicle passenger upon a vehicle collision, and more particularly to a curtain air bag device that is mounted on an inside side wall part of a vehicle cabin (or passenger room) and expands a curtain-like air bag to protect both front and rear seat passengers upon a vehicle collision.
2. Description of the Related Art
In order to clarify the present invention, the background of the curtain air bag device will be briefly described in the following with the aid of published documents.
One of the curtain air bag devices hitherto proposed is shown in Japanese Laid-open Patent Application (Tokkai) 2003-291771, which has an elongate or curtain-like air bag that, when not in use, is compactly wound up and neatly received in an elongate holding space that extends from a front pillar to a rear pillar of the vehicle body along a roof side rail. When the vehicle encounters a vehicle collision, such as side-on collision or the like, the curtain like air bag is ejected from the elongate holding space while quickly expanding toward the interior of the vehicle cabin having an outside surface thereof pressed against inside surfaces of side windows (when closed) of the vehicle. With such expansion of the air bag, front and rear seat passengers, namely, side portions of their heads are safely protected.
More specifically, the curtain air bag device of the Japanese Laid-open Application comprises an elongate or curtain-like air bag (viz., air bag proper) that is sized to protect both a front seat passenger and a rear seat passenger, an inflator that feeds the air bag with an inflating gas, and a tension strap that is fixed to a front end of the air bag. Upon expansion of the air bag, the tension strap become tightened to retain the expanded air bag at a given right position.
The curtain like air bag is made of two (viz., inner and outer) base fabrics stitched up together and comprises a front expandable portion that protects the front seat passenger, a rear expandable portion that protects the rear seat passenger, a conduit portion that extends between respective upper parts of the front and rear expandable portions to fluidly connect the two expandable portions, and a non-expandable fabric portion that is not fed with the inflating gas.
The front and rear expandable portions are generally the same in size and shape.
The non-expandable portion is provided below the conduit portion and extends between the front and rear expandable portions. That is, upon expansion of the air bag, the non-expandable fabric portion serves as a retainer for retaining or keeping a given distance between the front and rear expandable portions. With such non-expandable fabric portion and the above-mentioned tension strap, the passenger head protection effect of the two expandable portions is assuredly carried out upon a vehicle collision.
In the curtain air bag device as mentioned hereinabove, it is very important to compactly and correctly wind up the air bag in a flattened condition before being set in the elongate holding space. More specifically, if the flattened air bag is not properly wound up, it becomes very difficult to properly set the wound up air bag in the given holding space. If the setting of the wound up air bag in the holding space is not made properly, effective and reliable expansion of the air bag is not expected upon a vehicle collision.
One measure for eliminating the above-mentioned difficulty is described in Japanese Laid-open Patent Application (Tokkai) 2004-175304, which is an automatic air bag folding device by which the flattened air bag is compactly wound up. Thus, the air bag thus compactly wound up can be easily put into a right position of the holding space.
The automatic air bag folding device of the publication will be briefly described in the following with the aid of FIGS. 8 to 11 of the accompanying drawings.
As is seen from the drawings, the automatic air bag folding device 100 generally comprises a table 111 that has an upper surface 110 on which a flattened air bag 101 is to be flatly placed. The table 111 has a pocket “P” whose bottom is denoted by numeral 121.
The automatic air bag folding device 100 further comprises an air nozzle (not shown) that feeds the flattened air bag 101 with a pressurized air to expand the air bag 101 thereby separating inner and outer base fabrics 101a and 101b of the air bag 101 from each other as shown in FIG. 8, and first and second pressing blocks 151 and 153 that, as is seen from FIG. 9, are moved leftward to compress the expanded portion of the air bag 101 to produce first and second flattened portions 102a and 102b that extend in opposite directions. As shown in FIG. 8, the table pocket “P” is so sized as to receive the expanded part of the air bag 101, and as shown in FIG. 9, the first flattened portion 102a is sandwiched between the first pressing block 151 and an after-mentioned third pressing block 140, and the second flattened portion 102b is sandwiched between the second pressing block 153 and a side wall of the table pocket “P”.
The automatic air bag folding device 100 further comprises a bobbin rod (or saber member) 158 that winds therearound a remained flattened portion 103 of the air bag 101 to produce a wound up mass 104 of the flattened air bag 101 as is seen from FIG. 10, and a pushing plate 155 that functions to push and place the first flattened portion 102a onto the wound up mass 104 as is seen from FIG. 11.
The automatic air bag folding device 100 further comprises a locating pin 131 that is projectable from the table 111 and the third pressing block 140 that receives the projected locating pin 131 to tightly put therebetween a given part of the flattened air bag 101 for assuring positioning of the flattened air bag 101 on the table 111. As shown, for assuring the positioning of the air bag 101, the given part is formed with an opening (no numeral) into which the locating pin 131 projects.
In the following, the process of winding up the flattened air bag by using the automatic air bag folding device 100 will described with the aid of the drawings.
First, a flattened air bag 101 is flatly placed on the surface 110 of the table 111, and then the given part of the air bag 101 is retained by the locating pin 131 and the third pressing block 140, as will be understood from FIG. 8.
Then, as is seen from FIG. 8, the first and second pressing blocks 151 and 153 are moved to a position near the pocket “P” where a first part of the flattened air bag 101 is tightly put between these two pressing blocks 151 and 153 and a second part of the flattened air bag 101 is placed in the pocket “P” without restraint. Then, as is seen from the drawing, by feeding the flattened air bag 101 with a compressed air, the second part of the air bag 101 is expanded and thus the inner and outer base fabrics 101a and 101b there of are separated from each other, as shown.
Then, as is understood from FIGS. 8 and 9, the first and second pressing blocks 151 and 153 are moved leftward in the drawing to compress the expanded portion of the air bag 101. With this, first and second flattened portions 102a and 102b of the air bag 101 are produced as is seen from FIG. 9.
Then, as is understood from FIGS. 9 and 10, the first and second pressing blocks 151 and 153 are moved away from the third pressing block 140 leaving the first and second flattened portions 102a and 102b therebetween.
Then, as is seen from FIG. 10, the remained flattened portion 103 of the air bag 101 is wound up by the bobbin rod 158 to form the wound up mass 104 of the air bag 101. As is seen from this drawing, by turning the bobbin rod 158 in a counterclockwise direction, the wound up mass 104 moves leftward, that is, toward the third pressing block 140 while enlarging the size thereof.
As is seen from FIG. 11, when coming leftward on the table 111, the wound up mass 104 finally falls into the pocket “P”. Then, the pushing plate 155 is moved in a given way indicated by an arrow “X” for placing the first flattened portion 102a onto the wound up mass 104, as shown.
Then, the bobbin rod 158 is pulled out from the wound up mass 104.
It is to be noted that the wound up mass 104 thus produced has a cylindrical, long and narrow shape whose axis extends in a direction perpendicular to the surface of the drawing of FIG. 11. As has been mentioned hereinabove, the wound up mass 104, which is the wound air bag 101, is received in the elongate holding space that is provided by the side upper limited area, viz., the side roof rail 9 (see FIG. 1) of the vehicle cabin.